Metal composition and method of manufacture



P tented Sept; j l, 1925 NATHAN H. AnAms, or SCHENEGTADY,

NEW YORK, Assmnon 'ro GENERAL mncrnrc COMPANY, A conronA'rmN on NEW aroma.

METAL comrosrrron" AND ianrnon or MANUFACTURE No Drawing.

trode for simultaneously subjecting Work to both pressure and to the heating eflect of an electric current, as in spot welding, and' resistance heating, or as a bearing material for uses involving heavy pressures. My invention also includes an improved method of-making this materials In my prior Patent, 1,477,797 of Dec. 18, 1923, I havev described a bearing material made by pressing a mixture of a hard material, such as tungsten, anda malleable metal, such as'copper, and then fusing the latter metal.

The material made in accordance with my present invention is stronger, more capable of resisting higher pressure and more uni-. form in composition than the material. described in my prior patent. Instead of being constituted by a miggture of hard material and a softer material in which the particles of refractory material are bound together by the softer metaL'the improved material consists of a mass of tungsten made by causing the tungsten particles to sinter and form a coherent mass preliminar to the introduction of the copper or other filler metal. In other words the tungsten particles are welded or fritted to each other and the malleablemetal fills the minute spaces left between the tungsten particles. -While the copper strengthens the mass the tungstenparticles are not imbedded in a ground mass of copper. A feature of my present invention, is the introduction of the copper, or other readily fusible metal into the sintered mass of tungsten in a fused state under reducing-conditions and preferably ma-' 'terially above the melting point of the more fusible metal. n

My invention can be illustrated with composition having physical properties,

- which a sintered metal mass having a porous about 1300 C. tobe preferable.

' pressures,

Application filed December 31, 1924.- Serial no. 759,218. g 1

specific reference to the formation of a tungsten-copper composition. In its preparation comminuted tungsten such as used, V

proceed in general by thesteps described in Coolidge Patent 1,082,933 of Dec. 30, 1913, but preferably instead of sintered by patent, the tungsten is sintered after t in a hydrogen furnace to a temperature at structure results, which is capable of taking up a substantial proportion of another metal. I find a preferable range of temperature for sintering to be about 1250 to 1350 C. In accordance with the Coolidge patent the shaped, powdered tungsten is sintered at about 1200 C. in a furnace-and then is-further sintered at a highertemperature bypassage of current through the tungsten. While .I may proceed by this sintering by passage of current does not occur at too high a: temperature, I find the single sintering in the. neighborhood of The tungsten article produced b the sintering process has a fair amount 0 mechanical strength and may be readily: machined if desired, but it cannot withstand high As the next step in carryin out my invention, cop-per or other suitable metal of only moderately high fusibility which will flow readily in the presence of hydrogen is introduced in a highly fluid state into the; 95

voids or pores within the-body of the tungsten. Copper is fused in contact with the.

sintered refractory metal and" preferably heated to a-temprature of about 1200 to 1300 (3., under non-oxidizin kconditions 100 preferably in hydrogen gas. I find that copier in the presence. of hydrogen, especia point, to render it highly fluid will very.

readily permeate the entire mass of sintered 1 tungstemapparently being drawn into the mass by capillarity. Any excessof copper left on ,the surface may be removed by machining. The resultin composition is hard,

strong and capable of resisting high pres- '110 two steps as described in the .Coolidge preliminary pressing operation by heating I method of tlieCool-idge. patent if the second 4 y when thus heated above its melting sures and shocks. When using copper as the impregnating metal the sintered tungsten Wlll take upabout 10% by weight of the copper.

My improved metal composition is substantially non-deformable when subjected to high pressure during use and has a relatively highelectrical and heat conductivity. It is particularly well suited for use as an electrode for resistance welding, for heating rivets, or other purposes requiring simultaneous application of high currents and high mechanical pressure to the work being heated.

It is also useful as a bearing material for purposes" requiring it. to

I resist high pressure during use.

I have not claimed herein an electrode for heating and exerting pressure on work, this being covered by an application filed by Robert T. Gillette,-Se ial No. 7 29,169, filed Jul 30, 1924..

at I claim as new and desire to secure by Letters Patent of the United States,

' of tungsten and 1. The method of makin a composition of hard and soft metals which consists in forming an article comprising particles of the desired refractory 'metal, heating said article to a temperature high enough to cause said particles to sinter into. a. porous coherent mass having' greater mechanical strength than the unsintered article and impregnating said mass with a more fusible metal.

2. The method of making a composition copper which consists in v forming a mass of smtered tungsten having a porousstructure and impregnating said mass with copper, the porosity of the sintered mass being chosen to take up about 10 per cent copper by weight.

3. The method of making a composition oftungsten and copper which consists in shaping finely divided tungsten into desired shaping finel .sired form,

form, heating to a temperature of about 1250 to 1350 C., and introducing into con tact with the resulting 'sintercd mass copper heated above the melting point, in a hydrogen atmosphere, thereby causing the copper to permeate the tungsten body.

6. A metal composition capable'of resisting mechanical hard metal' particles fritted to each other in'the form of a coherent, porous structure and a softer, more fusible metal filling the voids in said structure, saidmaterial being stronger than'a material consisting of the same constituents in which the hard particles hav not been fritted to each other.

7 A metal composition capable of resisting mechanical deformation comprising tungsten particles fritted to each other into a coherent mass having minute spaces between said particles and a filling of copper in said spaces, constituting about ten per cent by weight of the tungsten,

sition being strongerthan a composition in which the tungsten particles are not fritted to each other to form a coherent mass.

In. witness whereof, I have hereunto set my hand. this 30th day of December,

NATHAN H. ADAMS.

deformation comprising said compo- 

